title: Multinucleation regulated by the Akt/PTEN signaling pathway is a survival strategy for HepG2 cells.
abstract: Hepatocellular carcinoma (HCC) is non-responsive to many chemotherapeutic agents including etoposide. The aim of this study was to examine the survival strategy of the HCC cell line HepG2 after etoposide treatment. Here we analyzed and compared spontaneous and etoposide-induced DNA damage in HepG2 (α-fetoprotein (AFP)-positive) and Chang Liver (AFP-negative) cell lines. Compared to Chang Liver cells, HepG2 cells exhibited a significantly higher degree of micronucleation and a higher nuclear division index, as determined by the cytokinesis-block micronucleus assay, following exposure to etoposide. HepG2 cells were also more resistant to etoposide-induced cytotoxicity compared to Chang Liver cells. We also establish that increased etoposide-induced multinucleation in HepG2 cells is dependent on the catalytic activity of Akt, as phosphatidylinositol-3-kinase inhibitors as well as the overexpression of kinase-defective Akt reversed this phenotype. Moreover, ectopic expression of wild type PTEN reduced the frequency of etoposide-induced multinucleated HepG2 cells, and restored HepG2 etoposide sensitivity. Taken together, these results implicate the Akt/PTEN cellular axis as a major determinant of the etoposide resistance of HCC cells.
authors.affiliation: Department of Life Science and Biotechnology, Jadavpur University, 188, Raja S.C. Mullick Road, Kolkata 700032, West Bengal, India.
authors.forename: Ananda
authors.initials: A
authors.lastname: Mukherjee
authors.forename: Sandip
authors.initials: S
authors.lastname: Misra
authors.forename: Niall G
authors.initials: NG
authors.lastname: Howlett
authors.forename: Parimal
authors.initials: P
authors.lastname: Karmakar
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002459:Cell Fusion; D002470:Cell Survival; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D004273:DNA, Neoplasm / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000502:physiology*; D005047:Etoposide / Q000494:pharmacology*; D015726:Giant Cells / Q000187:drug effects / Q000502:physiology; D006367:HeLa Cells / Q000187:drug effects; D056945:Hep G2 Cells / Q000187:drug effects*; D006801:Humans; D015162:Micronucleus Tests; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology*; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D059005:Topoisomerase II Inhibitors / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004273:DNA, Neoplasm; D009363:Neoplasm Proteins; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D059005:Topoisomerase II Inhibitors; D005047:Etoposide; D019869:Phosphatidylinositol 3-Kinases; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: Akt; Chang Liver; Cytokinesis-block micronucleus assay; HepG2; Multinucleation; PTEN